This invention relates to a read-off device for a medical testing appliance in which the sizes of columns of liquid held separated in a vessel of rod form, such as a capillary tube, are to be read-off, particularly in the case of component columns of a test sample separated by a centrifuging operation.
An object of the present invention to provide a simple and inexpensive device for the reading-off of the measuring values without the use of troublesome intermediary or comparison means. This object is met in the present invention by the fact that a read-off scale is arranged along the vessel and in a fixed relation to the latter, and the junction between the columns serves as a marker co-ordinating with the read-off scale. By these means the measuring values to be determined can be read from or beside the capillary tube or other vessel and the determination of the measurements thereby is greatly simplified and accelerated.
In the preferred embodiment of the invention an optical enlarging means is associated with the appliance to enable the read-off scale and the marker to be observed simultaneously. This greatly increases the accuracy of the measuring.
To prepare the measuring liquids for medical test purposes use is frequently made of a centrifuge, in the rotor of which a plurality of capillary tubes filled with test samples are clamped for centrifuging. The rotor holding the tubes is within a housing which can be closed by a pivoted cover. In this type of appliance it is advantageous, in accordance with a further feature of the invention, to make the optical enlarging means in the form of a lens which is arranged in the cover and can be brought with the latter into a predetermined read-off position, a read-off scale being provided in the rotor along each capillary tube. The predetermined read-off position is conveniently determined by a lateral arm of the cover which serves as an abutment cooperating with a counter abutment on the housing of the appliance. The lens can be secured in the cover as a separate element. The cover can however be made of transparent material and formed into a lens at a specific part of the material.